﻿//
// Synchronizer.cs
//
// Authors:
//   Alan McGovern alan.mcgovern@gmail.com
//
// Copyright (C) 2019 Alan McGovern
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//


using System.Collections.Generic;
using ReusableTasks;

namespace MonoTorrent
{
    class Synchronizer
    {
        public static Queue<Synchronizer> CreateLinked (int count)
        {
            var all = new List<Synchronizer> ();
            for (int i = 0; i < count; i++)
                all.Add (new Synchronizer ());

            all [0].Self.SetResult (true);

            for (int i = 0; i < count; i++) {
                all [i].PreviousNode = all [(i - 1 + count) % count];
                all [i].NextNode = all [(i + 1 + count) % count];
            }
            return new Queue<Synchronizer> (all);
        }

        public ReusableTaskCompletionSource<bool> Next => NextNode.Self;
        public ReusableTaskCompletionSource<bool> Self { get; } = new ReusableTaskCompletionSource<bool> ();

        Synchronizer PreviousNode;
        Synchronizer NextNode;

        public void Disconnect ()
        {
            PreviousNode.NextNode = NextNode;
            NextNode.PreviousNode = PreviousNode;
        }
    }
}
